MCQ On Class 12 Physics Chapter 3 Current Electricity

1 In a potentiometer of 10 wires, the balance point is obtained on the 7th wire. To shift the balance point to 9th wire, we should

A decrease resistance in the main circuit.

B increase resistance in the main circuit.

C decrease resistance in series with the cell whose emf is to be measured.

D increase resistance in series with the cell whose emf is to be determined.

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Answer:increase resistance in series with the cell whose emf is to be determined.

2 In parallel combination of n cells, we obtain

A more voltage

B more current

C less voltage

D less current

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Answer:more current

3 In the series combination of two or more than two resistances

A the current through each resistance is same.

B the voltage through each resistance is same.

C neither current nor voltage through each re-sistance is same.

D both current and voltage through each resis¬tance are same.

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Answer:the current through each resistance is same.

4 A charge is moving across a junction, then

A momentum will be conserved.

B momentum will not be conserved.

C at some places momenturii will be conserved and at some other places momentum will not be conserved.

D none of these.

View Answer

Answer:none of these.

5 In a Wheatstone bridge if the battery and galvanometer are interchanged then the deflection in galvanometer will

A change in previous direction

B not change

C change in opposite direction

D none of these.

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Answer:not change

6 When a metal conductor connected to left gap of a meter bridge is heated, the balancing point

A shifts towards right

B shifts towards left

C remains unchanged

D remains at zero

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Answer:shifts towards right

7 An electric heater is connected to the voltage supply. After few seconds, current gets its steady value then its initial current will be

A equal to its steady current

B slightly higher than its steady current

C slightly less than its steady current

D zero

View Answer

Answer:slightly higher than its steady current

8 The I-V characteristics shown in figure represents

Class 12 Physics Chapter 3 Current Electricity

A ohmic conductors

B non-ohmic conductors

C insulators

D superconductors

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Answer:non-ohmic conductors

9 AB is a wire of potentiometer with the increase in the value of resistance R, the shift in the balance point J will be

Class 12 Physics Chapter 3 Current Electricity

A towards B

B towards A

C remains constant

D first towards B then back towards A.

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Answer:towards B

10 Combine three resistors 5 Q, 4.5 Q and 3 Q in such a way that the total resistance of this combination is maximum

A 12.5 Q

B 13.5 Q

C 14.5 Q

D 16.5 Q

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Answer:12.5 Q

11 The resistivity of alloy manganin is

A Nearly independent of temperature

B Increases rapidly with increase in temperature

C Decreases with increase in temperature

D Increases rapidly with decrease in temperature

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Answer:Nearly independent of temperature

12 If n cells each of emf e and internal resistance r are connected in parallel, then the total emf and internal resistance will be

A

B ε,nr

C

D nε, nr

View Answer

Answer:

13 A cell having an emf E and internal resistance r is connected across a variable external resistance R. As the resistance R is increased, the plot of potential difference V across R is given by

A

Class 12 Physics Chapter 3 Current Electricity

B

C

D

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Answer:

14 Thermo electricity was discovered by:

A Joule

B Peitier

C Thomson

D Seebeck

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Answer:Seebeck

15 When the wires are connected in parallel, the heat produced in the thinner wire is H₁ and that in the thicker wire is H₂ Then:

A H₁ = H₂

B H₁ < H₂

C H₁ > H₂

D H₁ ≥ H₂

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Answer:H₁ < H₂

16 A wire P is half the diameter and half the length of a wire Q of similar material. The ratio of resistances of P to that 0 is:

A 4 : 1

B 8 : 1

C 2 : 1

D 1 : 2

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Answer:2 : 1

17 In a Wheatstone bridge, the resistance each arm is 10 Ω. If the resistance galvanometers is also 10 Ω, then effective resistance of the bridge will be :

A 40 Ω

B 20 Ω

C 10 Ω

D 5 Ω

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Answer:10 Ω

18 Two bulbs 25 W, 220 V and 100 W, 220 V are given. Which has higher resistance?

A 25 W

B 100 W

C both bulbs have equal resistance

D resistance of bulbs can not be compared

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Answer:25 W

19 In India electricity is supplied fordomestic use at 220 V. It is supplied at 110 V in U.S.A. If the resistance of a 60 W bulb use in India is R. the resistance of a 60 W bulb for use in USA will be:

A 2 R

B R

C R/2

D R/4

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